The present invention relates to a method for transmitting data in a microprocessor system; and, more particularly, to a method for transmitting data by using a combined serial/parallel data transmission technique between a microprocessor module and an external memory module.
A microprocessor is generally used as a central processing unit(CPU) of a computer system, and actually executes a plurality of instructions stored in a memory module. The microprocessor serves to perform an operation function, a memory function, and a control function by executing the instructions; and is generally made of one-chip. For representative example, there are Pentium and Pentium-Pro microprocessors manufactured by Intel Co., and 63000 series microprocessors of Motorola Electronics and Communications Inc.
The microprocessor has been initially designed for processing 4-bit data. Later, the size of data to be processed at a time was increased from 8 bits to 16 bits and, on these days, a microprocessor having 32-bit data size is generally used. As a high-performance microprocessor, a 64-bit microprocessor is already developed and commercially used. In addition, a microprocessor only for graphic usage is developed and used in order to process 128 bits data at a time.
Therefore, it is important to increase the size of data which can be processed at a time, and the performance of microprocessor can be greatly improved by increasing the size of data which can be processed at a time. Therefore, in the future, 128-bit and 256-bit microprocessors will be used in the microprocessor system.
However, as improving of the microprocessor, there occurs one important problem. According to the size of data to be processed at a time(the number of bits which can be processed at the same time), the bus having data lines identical to the size of data should be connected from a microprocessor to an external memory module. However, there is a limitation of pin numbers that can be attached during packaging of the microprocessor, so it reaches uppermost limitation to define the maximum size of data. That is, a 256-pin microprocessor should be connected through a data bus of 256-bit to the external memory module.
Furthermore, there are additional many control pins required necessary except for these data bus and address bus. That is, if the address bus of 64 bits is used, a 300-pin microprocessor is necessarily required. These pin number reaches nearly the maximum pin number that can be installed at a package by using a current packaging technology. Therefore, it is impossible to increase the size of data in a microprocessor having the limited pin numbers by using a conventional parallel data transmission technique.
It is, therefore, an object of the present invention to provide a method for transmitting data in a microprocessor system, which is capable of effectively overcoming the limitation of pin number caused by using a conventional parallel data transmission process.
A data transmission method employing a combined serial/parallel data transmission process in accordance with the present invention can be effectively used in a microprocessor system to overcome the limitation of pin numbers, caused when the data is processed at a microprocessor by using a conventional parallel data transmission process.
In accordance with the present invention, there is a provided a method for transmitting data between a microprocessor and an external memory module through external package pins comprises the steps of :a) dividing N-bit full sized data to be transferred by using M, wherein N and M are positive integers and N is greater than M; b) sequentially transferring N/M number of M-bit divided data; c) temporarily storing N/M number of M-bit divided data; and d) combining the N/M number of M-bit divided data into the N-bit full sized data.